JPS61144411A - Expanding joggle - Google Patents

Abstract

A metal expansion dowel is made up of an axially elongated cylindrically shaped expansion sleeve and an expansion element formed monolithically with the sleeve. The expansion sleeve has a leading end and a trailing end. The sleeve has an opening with the opposite edge surfaces extending in the axial direction converging toward the leading end. The expansion element is located in the opening and is secured to the sleeve by a separable web. The expansion element is wedge-shaped and narrows in the leading end direction. An inwardly projecting stop is formed in the expansion element. When an axial force is directed toward the leading end against the stop, the web is separated from the sleeve and the expansion element is displaced axially toward the leading end of the sleeve moving along the opposite edge surfaces of the opening and widening the sleeve. Due to the converging arrangement of the opposite edge surfaces of the recess, the dowel has a post-expansion characteristic during subsequent axial loading of the expansion sleeve after it is anchored in place.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has load receiving means in the rear end area, and at least one
The two dowels have a tapered cutout towards the longitudinally extending front end, which cutout expands to provide for a correspondingly wedge-shaped tapered expansion element. This invention relates to an expansion dowel with a cylindrical expansion tube whose element laterally abuts against the side surface of the resection.

Expansion dowels of the above type are mainly installed in the central load area or the lower load area and are made from sheet metal by stamping or roll forming processes. These dowels are being used in large quantities to replace conventional dowels made of synthetic materials because they meet the current requirements placed on dowels for fire safety.

However, since they are used in large quantities, the cost burden of these dowels increases.

Another advantage of these dowels over synthetic dowels is that they provide an additional expansion effect.

Known metal dowels of this kind consist of an expansion tube with a cutout tapering towards the front end for a wedge-shaped tapered expansion element.

Since the expansion tube and the expansion element are made separately, they must be assembled later and releasably connected to each other by other means until the dowel is installed in the borehole. With this method of manufacture, the dowels have high finishing costs and are considerably more expensive than those made from synthetic materials.

The object of the invention is to provide a metal expansion dowel which is economical to manufacture, simple to use, reliable and which has the above-mentioned advantages over dowels made of synthetic material.

According to the invention, this object is achieved in that the expansion element is connected to the expansion tube via a predetermined separation point.

At the point where the separation is scheduled, the expansion element is connected to the expansion tube body until the expansion process begins, and when it is installed, it must be broken in order to cause the axial movement required for expansion of the dowel. Reduce the strength of the parts.

The intended separation point is formed, for example, as a soldering, welding or gluing point. In this case, in order to manufacture the dowel economically, it is preferable to form the portion to be separated as an expansion element integrated with the expansion tube.

In this way, the expansion tube body and the expansion element can be stamped out of the same material in the same working process. Since punching waste is reduced, work time and materials can be saved. Post-processing of the punched material is also significantly easier. For example, the expansion element can be made in a shape corresponding to the expansion tube at the same time as the expansion tube is rolled.

Formation of a surface protective film can also be performed in the same processing step.

In principle, the separating piece can be arranged at various positions on the spreading element. It is advantageous to arrange the separating piece in the lateral area of the cutout, in particular in order to break the separating piece during installation. If the separation piece is arranged laterally in this way, the separation piece will be sheared off when the expansion element is separated from the expansion tube. The force required to shear the separation pieces can be determined relatively accurately. Therefore, the dimensions of the separation piece can be determined so that the force required to break the separation piece is within a predetermined range.

In order to prevent the spreading element from tilting when the separating piece is broken, it is preferable to arrange the separating piece at the rear and front side of the spreading element.

In this case, the separation piece is formed, for example, as a localized material weakening. Depending on the structure of the separation piece, it can be sheared or torn by tensile loads. The tearing section or the shearing section can be distributed over several separate pieces arranged at the rear front of the expansion element.

To manufacture this dowel, a particularly flat sheet metal is stamped out and then rolled into a tube. In this case, the expansion element is bent into an arc with a cross section that corresponds to the radius of the expansion tube. To simplify this task, the separating piece extends circumferentially along the rear end face of the expanding element. The cross section of the separating piece may extend over the entire rear front face of the expanding element or may be reduced by suitable means such as through holes, grooves, etc.

A preferred embodiment of the invention is characterized in that the circumferential dimension of the rear front face with the separation piece of the expansion element is smaller than the circumferential dimension of the wedge-shaped tapered portion at a position axially spaced from the rear end thereof. have This means that the widest position of the spreading element is not at its rear end, but approximately in the central area of the spreading element. For example, the spreader element may be wedge-shaped tapered from its widest point to its rear end. In this way, the width of the cut portion of the expansion tube can be reduced to the rear end. This increases the cross section of the expansion tube. This is extremely important if the expansion tube has an internal thread, for example. The notch effect can be eliminated by rounding the corners of the cut.

In order to expand the dowel using the broken separation target piece, it is necessary to move the expansion element in the axial direction with respect to the expansion tube. This takes place, for example, by applying a tensile load to the expansion tube. In order to effect the relative movement, the expansion element must protrude radially from the expansion tube and rest against the wall of the borehole like a barbed hook. However, this cannot be guaranteed due to the tolerances of the bored holes.

In order to facilitate this expansion of the expansion dowel, preferably the separation piece having the intended separation location is formed as a striking protrusion projecting into the bore of the tube. In this case, the dowel is expanded by means of a rod-shaped or pin-shaped fitting that is inserted into the expansion tube and rests on the percussion lug. If a force acting in the axial direction is applied, for example by a blow, which can be applied by a working device such as a hammer drill or by hand, the separation piece is broken by hitting this installation tool and then the expansion element is installed in the direction to expand the expansion tube body in the radial direction.

The invention will be explained with reference to the illustrated embodiment.

The expansion dowel shown in FIGS. 1 to 4 consists of an expansion tube body 1 and an expansion element 2. The expansion dowel shown in FIGS. The tubular body 1 has a front end 1a and a rear end 11b, and further narrows toward the front end 1a and has a cut-out portion 1c. Since the tube 1 is made by winding a strip, a vertical slit 1d is formed in the area following the rear end 1b. In order to prevent the tube from widening in this area, the front edges that meet at the longitudinal slit 1d are joined together, for example by soldering or welding. Expansion element 2
is tapered in a wedge shape corresponding to the cutout part 1c, and when the dowel is completed, it laterally abuts against the side surface of the cutout part 1c.

The element 2 is connected in one piece to the tube 1 by a breakable separation piece 3. Therefore, as shown in FIG. 4, the element 2 and the tube 1 are made in the same processing step. A striking protrusion 2 protruding into the inner bore of the tube body 1 in order to break the separating piece 3 or to displace the element 2 in the axial direction in the expanded position using an expanding tool (not shown).
a is provided in the element 2. As a connecting means, the tube body 1 has an internal thread 1e in its rear region.

The embodiment of the expansion dowel according to the invention shown in FIGS. 5 to 8 consists of an expansion tube 11 and an expansion element 12. The difference between this and the embodiment of FIGS. 1 to 4 is that the expansion element 12 is formed symmetrically. A separation piece 13 that joins the element 12 and the tubular body 11 is arranged at the rear front of the element 12 and extends in the circumferential direction. Depending on the manufacturing conditions, a vertical slit 11d is formed in this tubular body 11 as well. The tube body 11 also has an internal thread lie. The circumferential dimension "b" of the rear front face with the separation piece 13 of the element 12 is less than the circumferential dimension "B" at an axial distance from the rear end of the wedge-shaped taper. Therefore element 12
is formed with a wedge-shaped taper toward the front end 11a and rear end 11b of the tubular body 11. In order to make the cutout 11C have a shape corresponding to this, the cross section is greatly reduced at a portion other than the rear end of the cutout 11c. This prevents the area weakened by the internal twist of the tube body 11 from tearing when an axial load is applied.The expansion element 12 has a separating piece 13 at its rear end.
form (with a dent).

As shown in FIG. 7, the separation piece 13 consists of a locally weakened portion of the material. However, this is due to the element 1 protruding into the inner hole of the tube body 11.
It may be formed as two striking protrusions 12a.

In order to expand the dowel or break the separation piece 13, a bottle-shaped expander is inserted into the hole of the tube body 11 until it hits the striking protrusion 12a. Resection part 1 for better guidance of the expander
A vertical groove 11f is provided in the tube body 11 on the side opposite to 1C. After the separation piece 13 is broken, the element 12 expands the tube body 11 in the radial direction by impact force or axial pressure, so that the front end 1
It is pushed towards 1a. In this case, the expanding element 12
1C is pressed radially outwardly against the wall of the borehole. An additional expansion effect occurs when the expansion tube 11 is subjected to an axial load.

[Brief explanation of the drawing]

Fig. 1 is a front view of the expansion dowel of the present invention; Fig. 2 is a sectional view of the dowel in Fig. 1 along the line ■-■; Fig. 3 is a longitudinal sectional view of the dowel in Figs. 1 and 2. ; FIG. 4 is a developed view of the dowels in FIGS. 1 to 3; FIG. 5 is a front view of another embodiment of the present invention; FIG. 6 is a cross-sectional view of the dowels in FIG. 5 on line VT-VI; FIG. 7 is a longitudinal sectional view of the dowel shown in FIG. 5; FIG. 8 is a developed view of the dowel shown in FIGS. 5 to 7. 1.11... Expansion tube body 1c... Resection part 1d.
... Vertical slit) 2.12 ... Expansion element 2a
, 12a...Blowing protrusion 3, 13...Separation piece 1
1f...Groove patent applicant Hilti Akchengesellschaft J
EEi:3 2EEii:4 Ni&?

Claims (1)

[Scope of Claims] 1. A load-receiving means in the rear end area and a cutout tapering towards the longitudinally extending front end of at least one dowel, the cutout corresponding thereto; An expansion dowel with a cylindrical expansion tube, which is provided for an expansion element designed with a wedge-shaped taper so that the expansion element abuts laterally against the side of the resection. , the expanding element (2, 12
) is connected to the expansion tube body (1, 11) via a portion to be separated. 2. The area to be separated is the expansion element (2, 12) with the expansion tube (
2. Expansion dowel according to claim 1, characterized in that it is formed as a separate piece (3, 13) that is connected in one piece with the dowel (1, 11). 3. Expansion dowel according to claim 2, characterized in that the separation piece (3) is arranged in the side area of the cutout (1c). 4. Expansion dowel according to claim 2, characterized in that the separation piece (13) is arranged in the rear front area of the expansion element (12). 5. Expansion dowel according to claim 4, characterized in that the separation piece (13) extends circumferentially along the rear front side of the expansion element (12). 6. The circumferential dimension (b) of the rear front surface of the expanding element (12) with the separation piece (13) is the circumferential dimension (B) at a position spaced apart in the axial direction from the rear end of the wedge-shaped tapered part. ) The expansion dowel according to claim 5, characterized in that the expansion dowel is smaller than .). 7. Any one of claims 2 to 6, characterized in that the separation piece (13) having the intended separation location is formed as a striking protrusion (12a) projecting into the inner hole of the tube body. Expansion dowel described in .